Food, clothing, & shelter are the three basic human needs. Tens of millions of people around the globe have no home. In mature civilizations, like the United States, housing costs and interest rates have put home ownership out of reach of many millions of people.
The criteria for the ideal housing structure to meet the above need include: utilization of materials that are low cost & easily available; a structure that is easily and quickly erected, substantial, & attractive; utilization of minimal amounts of labor with minimal skill levels; low cost; minimal construction time; utilization of low-cost construction equipment which is easily used, easily maintained, easily transported, & easily repaired.
The prior art includes numerous examples of attempts to fulfill these objectives, all of which are subject to numerous deficiencies.
The following is a summary of the prior art related to methods and apparatus for the construction of low cost structures,
a. The International Basic Economy Corporation's system in Puerto Rico used a huge integral steel form to cast all the walls of the house integrally. First, the floor slab was poured, Then, reinforcing bars for the walls were assembled, and tied in place. After the slab cured, a huge crane set the steel form (consisting of an outside wall and an inside wall-between which the concrete was poured) in place on the slab. Then the concrete was poured, and vibrated to eliminate air pockets. Days later, the huge form was stripped away by the huge crane, cleaned, & set in place to pour the next house. The problems with his system include: long cycle time per house, the use of a very expensive steel form, a requirement for vibrating the concrete, a huge crane needed, many laborers needed--including highly-skilled & expensive crane operator, foreman, & engineer; a need to use reinforcing bars; and a need to assemble & tie the reinforcing bars all in place.
b. Another example of a building system utilizes re-useable steel or aluminum form panels, which are used to support the inner and outer surfaces of the concrete walls as they are poured, The problems with this system include: a relatively large amount of labor to assemble in place; a need for stripping and cleaning the panels after each use; the need for disassembling of the panels after each use, and the need for vibrating of the concrete to prevent airpockets.
c. Another example of a building system uses tilt-up construction where the floor slab is used as the form for the casting of wall and roof slabs which are then tilted up into position. The problems with this system include: long cycle time per house; corner posts have to be formed & cast to hold the walls together in the four corners of the house, and getting the roof slab on top of the walls takes substantial effort.
d. Another building system utilizes pre-cast concrete parts. The problems with this system include: major investment required to establish a casting plant; cracking & breaking of pre-cast parts between factory and final assembly; substantial effort is required to seal the pre-cast parts into an integral structure and the cost of truck operating to deliver parts from factory to the building sites.
e. Still another building utilizes a spray-on balloon structure. Problems with this system result from the igloo shape of the structure. The igloo shape is not attractive to customers because the non-vertical walls create waste space immediately adjacent to them, as a result of their angle to the floor. People are generally uncomfortable in rooms that do not have vertical, flat, and parallel walls because it seems to disturb their needs for a rectangular frame of reference and land plots are generally rectangular, not round so a round house does not fit its's land well.